1. Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Schleswig-Holstein (UKSH), Campus Kiel, and Christian-Albrechts-University Kiel, Kiel, Germany
2. Clinic of Otorhinolaryngology, University of Leipzig, Leipzig, Germany
3. Department of Radiation Oncology, University of Erlangen-Nuremberg, Erlangen, Germany
4. Clinical Trial Unit, UMG, University of Göttingen, Göttingen, Germany
5. Institute of Medical Informatics and Statistics, Christian-Albrechts-University Kiel, Germany